The invention relates to a system for control of devices, and especially to a system for wireless control of lighting.
Systems for the control of lighting are known in which keypads, switches, or other controls, hereinbelow generally referred to as xe2x80x9cevent initiatorsxe2x80x9d are operated by a user, the event initiators communicate to a central processor, and the central processor communicates to the various lighting control devices. One such system is the HomeWorks(copyright) Interactive(trademark) lighting control system manufactured by Lutron Electronics Co., Inc. of Coopersburg, Pa., U.S.A. The HomeWorks(copyright) Interactive(trademark) system is designed to operate primarily with hard-wired connections between the various components of the system.
Lighting control systems using radio communication between separated components are also known. One such system is the RadioRA(trademark) lighting control system manufactured by Lutron Electronics Co., Inc. Wireless systems are quicker and easier to install and reconfigure than hard wired systems. However, the radio frequency power and bandwidth available are usually limited by both regulatory and practical considerations. The frequency spectrum available is also used by many other systems. For example, the U.S. Federal Communications Commission allows low power, intermittent transmissions over a wide range of frequencies, including not only this sort of wireless control system, but also security systems, garage door closers, and the like. However, a large percentage of the range of frequencies is used by licensed operators, allowing only a small percentage of the range for use by unlicensed operators. Domestic lighting control systems need to be able to operate unlicensed, and therefore in the small percentage of unlicensed operator space.
Within that small space, interference among operators further limits the range of available frequencies at any given location. Because of the possibility of interference, and the need to operate at low power levels, it is also highly desirable to assess the quality of radio communications between devices within a wireless lighting control system. A measure of the quality of radio frequency communications is the probability of receiving a valid signal. Methods of assessing radio communications quality include measuring bit error rate, measuring ambient noise levels, and measuring the received signal strength of an intended signal, among others.
It is therefore an object of the present invention to provide improved control systems, and methods of installing and operating such control systems, that are especially suited to the wireless control of lighting installations, and to provide lighting installations equipped with such control systems.
In one aspect, the invention provides a method of remote control of devices, comprising: detecting operation of at least one control by a user; predicting whether the event commanded by said operation of said at least one control will result in a change of state of a display; updating said display if the predicted state of said display differs from the state of said display before said operation of at least one control; transmitting a command indicative of said operation of said at least one control; receiving a response indicative of an event that actually occurred in response to said transmitted command; determining a correct state of said display; and updating said display if said correct state of said display differs from the state of said display as updated on the basis of said prediction.
In another aspect, the invention provides an event initiator that comprises:
at least one control operable by a user; a display; and a transmitter and receiver for sending commands and receiving responses; and wherein said event initiator is adapted to: detect operation of at least one control by a user; predict whether said operation of said at least one control will result in a change of state of said display; update said display if the predicted state of said display differs from the state of said display before said operation of at least one control; transmit a command indicative of said operation of said at least one control; receive a response indicative of an event that actually occurs in response to said transmitted command; and update said display if a state of said display correct in view of said response differs from the state of said display as updated on the basis of said prediction.
In another aspect, the invention provides an event initiator for a wireless lighting control system, comprising: at least one control operable by a user; a transmitter for sending commands to another unit within the system in response to operation of said at least one control; and a memory storing a control model that relates operations of said control to commands sent. The control model identifies operations of the control that denote valid commands, and associates a transmissible command with each identified operation.
In another aspect, the invention provides a lighting control system comprising at least event initiators having controls operable by a user and devices controlled by said event initiators, wherein: the event initiators and controlled devices comprise parts of a system database; the database part within each event initiator maps operations of controls by a user to commands transmissible from such event initiator to said controlled devices; the database part within each controlled device maps commands received from an event initiator to actions of such device; and the transmissible commands contain less data than is necessary to describe completely the operations of controls or the actions of devices.
An event initiator for a wireless lighting control system that comprises a plurality of sub-nets each operating on a different radio channel, the event initiator comprising: a database of said channels; and a transmitter and receiver capable of operating on any of said channels. The event initiator is arranged, upon activation, to search through channels in its database for an active sub-net of the system with which it can communicate.
In another aspect, the invention provides a method of assessing the quality of radio communications within a wireless lighting control system, the wireless lighting control system comprising a plurality of wireless transmitter/receivers, comprising the steps of: transmitting a signal from one wireless transmitter/receiver within the system; causing other wireless transmitter/receivers within the system to measure the strength of the signal they receive; and compiling a record of measured signal strengths.
In another aspect, the invention provides a method of selecting an operating channel for a radio frequency system, comprising the steps of: tentatively selecting a first channel; communicating on a second channel while determining whether the tentatively selected channel is suitable for communication; if the tentatively selected channel is found to be unsuitable, tentatively selecting a different channel, and repeating said steps of communicating, and determining; and when a tentatively selected channel is found to be suitable, starting to communicate on that channel as the operating channel.
In another aspect, the invention provides a method of selecting an operating channel for a radio frequency system, comprising the steps of: tentatively selecting a first channel; communicating on said tentatively selected first channel, while determining whether said tentatively selected first channel is suitable for communication; if said tentatively selected first channel is found to be unsuitable, tentatively selecting a different channel, and repeating said steps of communicating, and determining; and when a tentatively selected channel is found to be suitable, starting to communicate on that channel as the operating channel.
In another aspect, the invention provides a method of selecting an operating channel for a radio frequency system, comprising the steps of: providing a plurality of devices capable of communicating on a plurality of channels; tentatively selecting a first channel; causing the devices to communicate on a second channel; on the second channel, announcing the tentatively selected channel to the devices; switching the devices to the announced channel; by the devices, detecting properties of the tentatively selected channel; reporting back the results of such detection from the devices on the second channel; from such results, determining whether the tentatively selected channel is suitable for communication; if the tentatively selected channel is found to be unsuitable, tentatively selecting a different channel, and repeating said steps of announcing, switching, detecting, reporting, and determining; and when a tentatively selected channel is found to be suitable, starting to communicate on that channel as the operating channel.
In another aspect, the invention provides a method of assessing the quality of an operating channel for a wireless lighting control system that has a plurality of transmitting and receiving devices, comprising the steps of: by the devices, detecting properties of the selected channel including at least one property selected from: an ambient noise level on the selected channel at the location of each device; and the presence or absence of a contending system using the same channel within radio range of any device; and determining from the detected properties whether the channel is suitable for communication.
In another aspect, the invention provides a method of operating a wireless lighting control system, comprising the steps of: receiving at an event initiator a command from a user; transmitting over a wireless link a command corresponding to the command; receiving a transmitted command at a lighting device controller; and altering the state of a lighting device, by the controller, within 300 ms after the command is received at the event initiator.
A method of operating a wireless lighting control system, comprising the steps of: receiving at an event initiator a command from a user; transmitting over a wireless link a command corresponding to the command; receiving a transmitted command at a lighting device controller; altering the state of a lighting device, by the controller; and displaying at the event initiator, within 1.5 s after the command is received at the event initiator, an indication of the state of said lighting device after said altering step.
In another aspect, the invention provides a method of operating a wireless lighting control system that comprises a central controller and a plurality of remote devices that are in communication over a wireless link with said central controller and are programmed with an operating system, the method comprising: uploading an operating system to said remote devices by wireless communication.